Mowers and mower-conditioners typically operate within a ground speed range from 5 to 10 mph when mowing. When the vehicle is operated at this speed, crop flows into the header at this rate, is temporarily accumulated, and then expelled out the rear of the mower-conditioner to form a windrow. The uniformity of the formed windrow density (defined as quantity of crop per unit area) is constant as long as the forward travel speed of the mower-conditioner is unchanged. However, when the forward speed is reduced significantly, much of the crop that has been accumulated in the header at the higher speed is expelled from the rear of the mower-conditioner at this significantly reduced speed resulting in a bunching up of the crop with an attendant increase in the windrow density. The bunched up crop dries slower than the crop in the remaining portions of the windrow that is formed at a lesser crop density causing a delay in the time that the crop can be baled without resulting in spoilage. It is noted that bunched up crop occurs most of the time at the headlands of the field when the operator slows down to turn the mower-conditioner around for the next pass through the field.
Accordingly, what is needed is some way to prevent crop from bunching up during a significant reduction in the ground speed of the mower-conditioner, as when turning at the headland of a field during mowing operation.